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Abstract:

Methods and apparatus are described for modifying unwanted tissue for
cosmetic reasons. The methods provide a non-invasive manner to perform
body contouring by destroying adipose tissue while simultaneously causing
collagen contraction in a single procedure so that as destroyed tissue is
removed from a treatment volume, the volume shrinks gradually to maintain
the skin tone of the treatment area. The procedure may involve multiple
treatments to the same treatment area or location.

Claims:

1. A method of modifying adipose tissue using high intensity focused
ultrasound energy, the method comprising: determining a volume of adipose
tissue to be treated; identifying a corresponding surface area of skin
over the volume of adipose tissue; moving a therapy transducer on the
surface area of skin; and applying multiple treatments of the high
intensity focused ultrasound energy with an energy flux less than 35
J/cm2 into a targeted volume of the volume of adipose tissue.

2. The method of claim 1 further comprising: marking the corresponding
surface area of skin to create a plurality of guide markers at a
predetermined spacing within the corresponding surface area.

3. The method of claim 1 wherein a temperature of the adipose tissue in
the targeted volume is less than 37 degrees Celsius between consecutive
treatments of the multiple treatments and is greater than 37 degrees
Celsius after the multiple treatments are applied.

4. The method of claim 1 further comprising: during the application of
the multiple treatments, reducing a velocity at which the therapy
transducer is moving.

5. The method of claim 4 wherein the adipose tissue in the targeted
volume includes a lesion field at the focal zone of the therapy
transducer and a halo field surrounding the lesion field, and applying
the multiple treatments of the high intensity focused ultrasound energy
further comprises: increasing a size of the halo field from the reduction
in the velocity at which the therapy transducer is moving.

6. The method of claim 1 further comprising: during the application of
the multiple treatments, increasing a velocity at which the therapy
transducer is moving.

7. The method of claim 6 wherein the adipose tissue in the targeted
volume includes a lesion field at the focal zone of the therapy
transducer and a halo field surrounding the lesion field, and applying
the multiple treatments of the high intensity focused ultrasound energy
further comprises: decreasing a size of the halo field from the increase
in the velocity at which the therapy transducer is moving.

8. The method of claim 1 wherein moving the therapy transducer on the
surface area of skin comprises: during the application of the multiple
treatments, moving the therapy transducer to form a plurality of scan
lines that overlap.

9. The method of claim 8 wherein the adipose tissue in the targeted
volume includes a lesion field at the focal zone of the therapy
transducer and a halo field surrounding the lesion field, and the halo
fields of the scan lines overlap.

10. The method of claim 8 wherein the scan lines are aligned parallel to
each other.

11. A method of modifying a targeted volume of adipose tissue in a
patient using high intensity focused ultrasound energy, the method
comprising: applying a first set of one or more treatments of the high
intensity ultrasound energy into the targeted volume of the adipose
tissue, the first treatment set subjecting the targeted volume to a
cumulative first energy flux so that the first treatment set does not
cause a temperature of the adipose tissue in the targeted volume to
exceed a predetermined temperature; and following the application of the
first treatment set, applying a subsequent treatment of the high
intensity ultrasound energy into the targeted volume of the adipose
tissue, the subsequent treatment subjecting the targeted volume to a
second energy flux so that the combination of the first cumulative energy
flux and the second energy flux causes the temperature of the adipose
tissue in the targeted volume to exceed the predetermined temperature.

12. The method of claim 11 wherein the second energy flux is not greater
than the first energy flux.

13. The method of claim 11 wherein the predetermined temperature is not
greater than approximately 56 degrees Celsius.

14. The method of claim 13 wherein the predetermined temperature is not
greater than approximately 46 degrees Celsius.

15. The method of claim 14 wherein the predetermined temperature is
approximately 37 degrees Celsius.

16. The method of claim 11 wherein a pause in application of the high
intensity focused ultrasound energy to the adipose tissue in the targeted
volume occurs between the first treatment set and the subsequent
treatment.

17. The method of claim 16 further comprising: during the pause, treating
adipose tissue of the patient outside of the targeted volume with the
high intensity focused ultrasound energy.

18. The method of claim 11 wherein the first energy flux is less than 35
J/cm.sup.2.

19. The method of claim 18 wherein the second energy flux is not greater
than 35 J/cm.sup.2.

20. The method of claim 11 wherein the second energy flux is not greater
than 35 J/cm.sup.2.

Description:

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application is a continuation of application Ser. No.
12/559,239, filed Sep. 14, 2009, which claims the benefit of Provisional
Application No. 61/097,205, filed Sep. 15, 2008, and which is
continuation-in-part of application Ser. No. 11/414,080, filed Apr. 27,
2006 and issued as U.S. Pat. No. 7,857,773 on Dec. 28, 2010, which (1)
claims the benefit of Provisional Application 60/676,197, filed Apr. 29,
2005 and (2) is also a continuation-in-part of U.S. application ser. No.
11/026,519, filed Dec. 29, 2004 and issued as U.S. Pat. No. 7,993,289 on
Aug. 9, 2011, which claims the benefit of Provisional Application No.
60/533,958, filed Dec. 30, 2003. The full disclosure of each of these
applications is hereby incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to using ultrasound apparatus and
methods for the noninvasive modification of adipose tissue.

DESCRIPTION OF THE PRIOR ART

[0003] Body sculpting has developed into a highly sought after procedure
for restoring people to a leaner, trimmer physique. The field of cosmetic
surgery has ballooned considerably with developments in both tools and
techniques. One of the more popular for quick body sculpting is
liposuction.

[0004] Liposuction is a method of body contouring that can dramatically
improve the shape and contour of different body areas by sculpting and
removing unwanted fat. In the United States, more than 400,000
liposuction procedures are performed annually. Recent innovations and
advances in the field of liposuction include the tumescent technique and
an ultrasonic assisted technique. Traditional liposuction was done by
making small incisions in desired locations, then inserting a hollow tube
or cannula under the skin in the fat layer. The cannula is connected to a
vacuum and the fat is vacuumed out. This procedure indiscriminately
removed fat, connective tissue, blood vessels and nerve tissue. The
procedure caused bleeding, bruising, trauma, and blood loss; the
combination of which restricts the amount of fat that can be removed
safely in any given procedure.

[0005] The Tumescent technique allows for removal of significantly more
fat during the operation with less blood loss. Tumescent liposuction
involves injecting saline and adrenalin solution before suctioning. A
cannula is again used with a suction device to remove fat. This procedure
reduces the bleeding of traditional liposuction. However the procedure
still removes a significant amount of non-fat tissue.

[0006] A more refined liposuction technique is Ultrasound Assisted
Lipoplasty (UAL). UAL is similar to the Tumescent technique, but adds a
cannula (or probe) vibrating at ultrasonic frequencies. This vibration
disrupts the near volume fat cells and essentially liquefies them for
easy removal. UAL uses a low power suction and draws the fat material
only in the near vicinity of the cannula tip. This technique is more
refined and gentle to the tissue, there is less blood loss, less
bruising, less pain, and a significantly faster recovery. All liposuction
techniques are invasive and present risks of infection and surgery risks
to the patients who undergo these procedures.

[0007] Furthermore, once the underlying tissue is removed, the skin may
become baggy or loose. To combat loose folds of skin or sagging of skin
tissue, a patient may elect to have the extra skin removed (by undergoing
a skin excision operation) or elect a skin tightening procedure.

[0008] In addition to these invasive forms of liposuction, there are
numerous other techniques in the prior art for treating unwanted fat
(adipose tissue). These techniques, methods and compositions include, but
are not limited to; creams, lotions, garments, massage tools and
techniques, therapy procedures involving lasers, RF or ultrasound
equipment, general surgery, medication and a host of "home remedies."

[0009] Unfortunately none of these procedures provide a one step solution
for a patient. The norm is for a patient to undergo multiple treatments,
sometimes for the same "trouble spot" on the body, before the patient is
satisfied with the results. Techniques and instruments of the prior art
are designed for particular applications and operate within parameters
specific to one desired outcome.

[0010] Thus there remains a need for a single solution to the multiple
step problem of either removing or reducing unwanted tissue volume while
simultaneously providing for improved cosmetic appearance without the
need for secondary or follow on procedures.

[0011] There is also a need for a cost effective solution to provide for a
simple, quick and effective manner to achieve the desired objective or
producing a viable body sculpting procedure in one simple procedure.

BRIEF SUMMARY OF THE INVENTION

[0012] Thus it is an objective of the present invention to provide a
method and apparatus that can combine the effects of various cosmetic
procedures into a single non-invasive procedure that will eliminate or
greatly reduce the need for additional procedures.

[0013] It is another objective of the present invention to provide a means
for controlling the amount of energy needed to treat a problem site
depending on the patient and treatment volume.

[0014] These and other objectives are achieved through the use of a HIFU
ultrasound apparatus and methods for tissue modification.

[0015] In a first embodiment there is a method of modifying tissue using
high intensity focused ultrasound. The method comprises determining a
volume of adipose tissue to be treated, identifying a corresponding
surface area of skin over the volume of adipose tissue, moving a HIFU
therapy transducer over the surface of the skin and applying therapeutic
ultrasound energy into the volume of adipose tissue so that a plurality
of cells of tissue necrosis and denatured collagen fibrils are produced.

[0016] Alternatively the method may include marking the patient's skin
surface to create contour lines and/or guidelines for the HIFU therapy
transducer. The motion of the transducer may be continuous or
discontinuous. The application of therapy ultrasound energy may be done
while the transducer is moving or between segments of movement depending
on the desired energy distribution in the volume of adipose tissue. HIFU
energy is desirably focused in the volume of adipose tissue to raise the
temperature to a level where the adipose tissue is destroyed (or no
longer viable) and the collagen fibrils are permanently denatured.

[0017] In another embodiment of the present invention, there is an
apparatus for the delivery of HIFU energy into a patient. The apparatus
having at least one ultrasound transducer adapted for being moved while
applying therapy and being capable of depositing an energy flux (EF)
greater than 35 J/cm2, typically in the range from 35 J/cm2 to
460 J/cm2, wherein EF is determined by the formula:

[0018] Preferably, the apparatus is adapted to deposit sufficient
ultrasonic energy to produce an EF value greater than 109 J/cm2.
Additional embodiments and equivalents will be clear upon a detailed
study of the following description.

[0025]FIG. 11 shows a mosaic of treatment sites used to cover a treatment
area.

[0026] FIGS. 12-13 show histology slides of actual treated tissue.

[0027] FIG. 14 is a flow chart showing steps for providing multiple
treatments to a single location in accordance with an embodiment.

[0028] FIG. 15 is a representation of an ultrasound treatment pattern in
accordance with an embodiment.

[0029]FIG. 16 a block representation of a robot arm apparatus that may be
used in a procedure in accordance with an embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0030] It should be understood on reviewing the present disclosure that
the figures and drawing provided herein are illustrations only. Items
shown in these drawings are not intended to be to scale with respect to
any key or legend, nor to scale within each drawing. The illustrations
may exaggerate particular elements expressly for the purpose of
illustrating the element and assisting in the understanding of the
accompanying specification.

[0031] Methods to address the various issues of patient concern when
looking for a non-invasive alternative to liposuction are now described.
In one embodiment there is a method of modifying tissue using high
intensity focused ultrasound. The method comprises the steps of
determining a volume of adipose tissue to be treated, identifying a
corresponding surface area of skin over the volume of adipose tissue; and
moving a HIFU therapy transducer on the surface area of skin, and
applying therapeutic ultrasound energy into the volume of adipose tissue
so that a plurality of cells or pockets of tissue necroses and denatured
collagen fibrils are produced.

[0032] Determining a volume of adipose tissue to be treated is similar to
the pretreatment procedures used by cosmetic surgeons prior to a
liposuction procedure. A manual pinch test or caliper test can be used by
a trained physician to determine if a patient has sufficient adipose
tissue at a particular site to warrant a liposuction procedure. The
safety measure and standard used by such a test can also satisfy the
minimum requirements of a HIFU procedure such as described herein.
Alternatively, a physician may use an imaging instrument such as a
diagnostic ultrasound device, an MRI device, or a simple A-line scanner
to determine if there is sufficient adipose tissue depth in a desired
area to be treated using HIFU energy.

[0033] While the depth of the adipose tissue should be sufficient to allow
the focal zone of the HIFU transducer to be safely in the adipose tissue
with some margin of safety both above and below the focal point of the
transducer, it should be understood that varying the focal depth of the
transducer, as well as the shape and focus of the transducer can allow
for more precise control over the delivery of HIFU energy, while
simultaneously reducing the clearance zones needed for safe operation.
That is to say a highly focused transducer provides sufficient control
and focus to allow for a reduced safety clearance.

[0034] Once the volume of tissue is identified, the physician should
determine the corresponding surface area over the volume that can be
treated. Once again, borrowing from existing techniques in liposuction,
the physician may proceed directly to treating the patient using a HIFU
transducer, or she can create one or more contour lines as part of the
treatment planning phase of an ordinary liposuction procedure. During
this step the physician may draw or otherwise indicate on a patient skin
surface, a region that can safely be treated using a HIFU transducer.
Pens or markers may be used to create these contour lines.

[0035] Next is the application of HIFU energy into the volume of adipose
tissue. A HIFU transducer is moved over the surface area identified
above. The transducer emits energy to the focal zone in sufficient
strength (power) and intensity (pressure) to cause cellular necrosis and
collagen fibril denaturing. Depending on the pulse repetition frequency
and velocity that the transducer is moving, a plurality of discrete
treatment cells will be produced. Desirably each treatment cell will
absorb sufficient energy from the transducer to cause cellular necrosis
of all cells in the focal zone, as well as collagen denaturing in the
same region. The volume of tissue affected at the focal zone of the
transducer is the lesion field 630 (FIG. 3A-5B). The volume around the
lesion field 630 where adipose tissue is destroyed and/or collagen
fibrils are denatured is the halo field 6. If the transducer is moved in
a continuous manner such that a single linear lesion field is formed
along the path or axis of motion, the lesion field is said to be
contiguous, or a contiguous lesion field 630c. Similarly the halo field 6
may be a contiguous halo field 6c. A volume of over lapping lesion field
produced from more than one scan line (such as an intersection) forms a
cooperative lesion field, while overlapping halo fields are referred to
as cooperative halo fields. Overlapping halo fields may be produced by
operating the HIFU transducer in a manner such that scan lines intersect
one another, or run parallel close enough so their corresponding halo
zones overlap. The sum of the tissue volume of the various lesion fields
and halo fields produced during a therapy procedure comprises the
treatment area 3.

[0036] In accordance with an embodiment, the application of HIFU energy
into the volume of adipose energy may involve multiple treatments at the
same location. In such an embodiment, the cumulative strength (power) and
intensity (pressure) is sufficient to cause cellular necrosis and
collagen fibril denaturing. This cumulative effect permits each
individual treatment to be of insufficient power and intensity to cause
cellular necrosis and collagen fibril denaturing.

[0037] FIG. 14 is a flow chart showing steps for providing multiple
treatments to a single location in accordance with an embodiment.
Beginning at step 1400, a first application of HIFU energy (i.e., a first
treatment) is applied into a particular location in adipose tissue. At
step 1402, a pause is taken, in which treatment may be applied to another
location. At step 1404, an additional treatment is applied to the same
location. At step 1406, a determination is made whether the power of the
cumulative treatments is sufficient to cause cellular necrosis and
collagen fibril denaturing. If not, the process branches back to step
1400, and a further treatment is applied. If so, the applications at that
location may be completed.

[0038] It can be understood that such cumulative treatments may be
repeated to accumulate even more power, but at a minimum, the
accumulation is sufficient to cause cellular necrosis and collagen fibril
denaturing. Also, an evaluation need not be done after each treatment (as
indicated by step 1406), but instead the number of treatments at a given
location may be determined empirically or clinically. It should also be
understood that the application of energy to the treatment site may vary
from one treatment to another at the same location. For instance if it is
desirable to apply a value of X power and/or pressure to a region of
tissue, it may be applied in more than one application in which all
applications are equal, or in which the sum of the applications is X, but
each application is a different fraction of X. Once the desired
application of energy is achieved, the transducer is relocated to a new
location and the process may be repeated at a different location at step
1408.

[0039] The destruction of adipose tissue in the lesion field is not
restricted to adipocytes (fat cells) alone. The methods described herein
are intended to destroy biological tissue within the focal zone by
whatever mechanism the HIFU transducer can produce. Furthermore the
thermal energy which radiates from the lesion field destroys the
surrounding tissue forming the halo field. This thermal radiation is not
intended to be of a particular temperature for selective preservation of
any biological material. The temperature in the halo field should be
sufficient to destroy the adipose tissue and denature the collagen
fibrils. Thus, it is likely that other cells or tissue types within the
lesion and halo field will be destroyed.

[0040] In one embodiment, the application of HIFU energy may be done in a
manner to form a pattern of discrete lesion fields 630 and halo fields 6
within a treatment area 3. In another embodiment, the application of HIFU
may be done in a manner that divides the treatment area 3 into a
plurality of smaller treatment sites 2, and the sum of the treatment
sites 2 produces the desired coverage to form the treatment area 3 (FIG.
11). Alternatively, HIFU energy may be applied in either continuous or
discontinuous motion through individual treatment sites 2, or across the
entire treatment zone 3. The various treatment sites 2 which form the
treatment zone 3 on a patient may be uniform or different in both size of
each treatment site 2 within the treatment zone 3, as well as having any
mixture of lesion fields 630, contiguous lesion fields 630c, cooperative
lesion fields, halo fields 6, contiguous halo fields and cooperative halo
fields. In addition, for each treatment site, as described above,
multiple treatments may be provided, with the multiple treatments having
any of these forms.

[0041] In yet another embodiment of ultrasound application according to
the present methods, the transducer may be used to deposit energy and
produce lesion fields of varying shapes and sizes. If the transducer is
left to reside in a single position (such as using an incremental
movement), the transducer may initially create a small lesion field. By
allowing the transducer to loiter, thermal energy will build up and
radiate out from the lesion field. The transducer may be moved slowly or
have higher energy output while moved in a regular movement pattern to
produce larger contiguous lesion fields (produce thicker scan lines). By
analogy, one may envision the way a fountain pen leaves ink on a page.
Just as the nib of a fountain pen allows ink to spread across paper from
the point of contact of the nib, so too does thermal energy radiate out
from the focal zone of the transducer the longer the transducer is left
to loiter over a particular spot of adipose tissue. Some variations of
these lesions are shown in FIG. 8. Similar to those scan lines 4, lesion
fields 630 and halo field 6 previously described, there are now shown
enlarged halo fields. Here the scan line 4 may produce a spot shaped
lesion field 630 with a generally spherical shaped halo field 6.
Increasing the power broadcast into the tissue may be achieved by moving
the transducer slowly, varying the parameters of the transducer, so that
more energy radiates from the lesion field into the surrounding tissue,
thus producing an enlarged halo field. Similarly, the lesion field itself
may also increase in size.

[0042] Using the varied sizes along with multiple treatments for a single
location allows a number of variations. For example, as shown in FIG. 15,
large halo fields may be overlapped so that each location has four halo
effects at each lesion field. The system may be arranged so that the
cumulative power applied at each lesion field is sufficient to cause
cellular necrosis and collagen fibril denaturing.

[0043] The motion of the transducer over the patient skin can follow any
number of patterns. A basic motion is shown in FIG. 4A. Here a transducer
500 is moved in a linear path over the patient skin. The transducer has a
focal zone 630 which creates a lesion field. If the transducer is moved
in a controlled manner the lesion field formed by the HIFU therapy
transducer may form a single, contiguous line of destroyed tissue 630c.
The axis of the focal zone in tissue is referred to herein as the scan
line 4. Surrounding the scan line 4 is a region of thermal effect
desirably raising the local tissue to temperatures sufficient to kill
adipose tissue and denature collagen fibrils. This halo field 6 about the
scan line 4 represents the volume of tissue which receives sufficient
thermal radiation from the lesion field 630, 630c to also be destroyed
and denatured. The halo 6 may be large or small depending on how quickly
the transducer is moved, and how much power the transducer produces. Here
a single scan line 4 is shown within a single treatment site 2 for
clarity. A cross section view of a scan line 4 is shown in FIG. 4B.

[0044] For multiple treatments at the same location, a scan line may be
repeated. Alternatively, scan lines may cross or overlap to provide a
desired accumulation.

[0045] Alternatively, the transducer 500 may be made to produce high
intensity pulses or pulse bursts (rapid sequence of discrete pulses) to
produce discrete lesions 630 along a scan line 4 (FIG. 3A). In this
embodiment, the transducer is desirably moved over the patient skin
surface and the transducer is programmed to deliver discrete bursts of
HIFU ultrasound energy to produce individual or discrete "cells" of
destroyed tissue. The burst of ultrasound energy can produce any variety
and number of discrete lesions in the tissue. A halo 6 may also be found
surrounding each lesion depending on the operating parameters of the
transducer. Again, the pattern of lesion fields and halos are also
presented in cross section shown in FIG. 3B.

[0046] Another embodiment for applying ultrasound energy is illustrated in
FIGS. 5A-B. Here two scan lines 4, 4' are shown in close proximity so
that the contiguous lesion fields 630c, 630c' are parallel. The halo zone
6 of each scan line run together to form a region of cooperative effect
and enlarge the halo zone. Multiple scan lines may be placed side by side
to form a large layer of mechanical and thermal effect (FIG. 5B).

[0047] For multiple treatments at the same location, individual scan lines
may be repeated at the same location, or slightly moved over so as to
overlap a previous line. Alternatively or in addition to this
arrangement, scan lines may cross or overlap to provide a desired
accumulation. A large number of scan lines may be utilized for a
treatment area with several overlaps in the scan lines and so that
cumulative power at most or all locations is sufficient for cellular
necrosis and collagen fibril denaturing. Collagen denaturing can occur at
temperatures above 37° C. However denatured collagen at
temperatures close to normal body temperature may recover, relax and
resume their normal length. Desirably then, collagen in the treatment
zone is exposed to temperatures above 37° C. More desirably
collagen fibrils in the treatment zone are exposed to temperatures above
46° C. and even more preferably to temperatures above 56°
C. The higher the temperature the collagen fibrils are exposed to, the
shorter the length of time needed to achieve the desired effect
(permanent collagen denaturing for contraction of collagen fibrils). When
the exposure is at 46° C., the collagen fibrils need to be
incubated at that temperature for at least several minutes, however
exposure of collagen fibrils to temperatures near or above 56° C.
may be done in less than a few seconds. "Collagen Fibril" refers to the
collagen material found in adipose tissue or sub dermal regions where
collagen concentration tends to be sparse and used by the body as a
lattice connective tissue rather than a major structural component
(contrast with regions like the nose, ears, skin or tendons and the
like). Contraction of collagen fibrils refers to using thermal energy to
denature the collagen and force the collagen fibrils to shorten
lengthwise.

[0048] Desirably adipose tissue is heated using HIFU energy so the
temperature in the lesion field is raised as high as practical and as
fast as possible. Parameters of the HIFU transducer may be adjusted to
produce the desired fast heating needed to destroy adipose tissue and
denature collagen fibrils. Desirably the fast heating is balanced with
the volume and dimensions of the adipose tissue to be treated. The longer
the transducer remains active on one location, the larger the halo field.
Desirably the moving of the HIFU transducer and the applying of
therapeutic ultrasound energy do not produce lesion or halo fields which
extend beyond the dimensions of the adipose tissue volume.

[0049] Although using higher power and pressure produce faster results,
using higher power may cause some patient pain. The same or a similar
effect may occur, however, by using multiple lower power treatments at a
same location so that there is an accumulation of power resulting in a
similar treatment.

[0050] Additional parameters that affect the size of the lesion and halo
fields are those parameters electronically controlled through the
transducer, and parameters of the transducer itself. These parameters
include (but are not limited to) power, frequency, duty cycle, focus,
size (of transducer), and pulse repetition frequency.

[0051] In some applications, the size of the lesion and halo fields are
desirably minimized. This is particularly true where the adipose tissue
depth necessitates a tightly controlled lesion and halo field due to
proximity of muscle, organs or skin. This can be accomplished by
distributing the individual lesion fields within a treatment site apart
from each other in both distance and time. If the treatment site is
represented by a defined field area 2, then the individual spot lesions
may be laid down one at a time in a sequence from L1 to L15
(FIG. 6). For multiple treatments at each location, the sequence may be
repeated or may be performed in a different order. Here the lesions are
temporally separated as well as being spatially separated. This pattern
allows for the individual lesions to have a minimum cooperative thermal
effect between lesions. The size of each lesion (L1-n) may also be
controlled by adjusting the parameters of the ultrasound transducer used
in the treatment.

[0052] Alternatively, the lesion and halo fields may be maximized by
permitting the HIFU transducer to produce contiguous lesion fields and
cooperative halo fields. An example of such a maximizing movement scheme
is illustrated now in FIG. 7. In this embodiment, the energy required to
produce cellular necrosis and collagen contraction is lessened due to the
co-operative effect of having the transducer operate in narrowly spaced
treatment lines and in rapid succession of laying down treatment lines
near each other in both time and space. Movement of the transducer is
desirably machine controlled for uniformity and simultaneous control of
the transducer. The transducer can treat patient tissue volume by moving
over the surface of the tissue volume in any variety of patterns
including, but not limited to, spiral, raster scan, or patterned. Thermal
cooperation can be maximized by delivering the ultrasound energy as a
contiguous lesion field 630 within the treatment site 2. A raster scan
type pattern (FIG. 7) may be used with a relatively close line spacing to
provide for a maximum of thermal cooperation to produce a large halo
region. The horizontal scan lines 4 may be connected with vertical
transit lines 5 where the transducer is active, or the vertical transit
lines may be "empty" if the transducer is not active while moving
vertically. Likewise the spacing between the horizontal lines 4 may be
close together or physically overlapping to provide for the maximum
overlap of ultrasound energy. For multiple treatments on a same location,
as described above, the raster pattern may be repeated or different
crossing or overlapping patterns may be used to provide desired
accumulation at each location. Careful planning and consideration in the
applying of ultrasound energy in the methods described herein can produce
the desired volume of tissue modification in both the amount of adipose
tissue destroyed, and collagen denatured.

[0053] A balancing of speed (velocity of the focal zone in the tissue
being treated) and the power and intensity of the transducer are needed
to produce the desired effect. A method of determining the various
parameters to use in a tissue modification is now described. In this
embodiment, there is a method of reducing adipose tissue volume in a
patient using high intensity focused ultrasound. The method comprises the
steps of determining a volume of adipose tissue to be treated; marking
out a corresponding surface area of skin and applying high intensity
focused ultrasound energy to said area in a manner sufficient to induce
the gradual destruction of said adipose tissue and denaturing of collagen
fibrils, the energy flux being of at least than 35 J/cm2.
Operationally the speed of destruction may be quickened by providing
higher EF values. By scanning the transducer over a volume of adipose
tissue at higher EF values, the amount of time needed to achieve adipose
tissue necrosis and collagen fibril denaturing can be reduced. Using EF
values between 90 and 225 Joules per square centimeter allow for the
desired treatment to be done quickly. Further increasing the EF to higher
values also produces viable results under certain conditions, going as
high as 460 J/cm2.

[0054] Accumulation can provide a desired EF value without the application
of high energy flux pulses. For example, two separate treatments, each
having 33 J/cm2, may result is an accumulated EF of 66 J/cm2,
without having to resort to a treatment exceeding 35 J/cm2. As such,
efficacy may be enhanced with greater patient tolerance.

[0055] By using a predetermined energy flux value, the transducer can be
programmed to consistently and accurately deposit the same amount of
energy into each of the lesion fields (also referred to as the focal
zone). Through experimentation and analysis, we have found that tissue
ablation of adipose tissue and collagen contraction can occur at energy
fluxes above 35 joules per square centimeter. Variations in desired
outcomes and tissue variations from patient to patient make calling out
an exact energy flux figure impossible. However empirical data from
multiple study sources suggest the energy flux value, from cumulative or
a single treatment, should be greater than 35 joules per square
centimeter and are probably most efficacious for the dual purpose of
destroying adipose tissue and denaturing collagen fibrils at or above 109
joules per square centimeter.

[0056] In a physical embodiment of the present invention, there is an
apparatus for the delivery of therapeutic ultrasound energy into a
patient. The apparatus having at least one ultrasound transducer adapted
for being moved while applying therapy and being capable of depositing an
energy flux (EF) greater than 35 J/cm2, wherein EF is determined by
the formula:

[0057] The formulation provided provides for a calculation when the
transducer is moving continuously while applying ultrasound energy.
Alternatively for a treatment program where the transducer is not moving
between therapy applications, the EF can be calculated using the
following modified EF equation.

[0058] Variations in the formula can be derived by those skilled in the
art to determine the proper calculations for a therapy program having a
mixed set of moving and non-moving treatment sites. The therapy
controller desirably allows for a wide variation in parameters which a
user may manually feed into the therapy controller prior to each
application of ultrasound. The therapy controller determines which
variables are to be used and weights them accordingly. An example of a
medical instrument system for use with the methods described herein is
further described in co-pending U.S. patent application Ser. No.
11/027,912 entitled "Ultrasound Therapy Head with Movement Control", the
contents of which are hereby incorporated by reference herein in their
entirety.

[0059] Another example is described in co-pending U.S. patent application
Ser. No. 11/026,519 entitled "Systems and Methods for the Destruction of
Adipose Tissue" filed on Dec. 29, 2004, the contents of which are hereby
incorporated by reference herein in their entirety. The apparatus for the
delivery of therapeutic ultrasound energy into a patient has a scan head,
suspension device for supporting the scan head, and a therapy controller.
The therapy controller is adapted to monitor the position and energy
deliver of the scan head. This apparatus may be used to deliver multiple
treatments to the same location by having the scan head return multiple
times.

[0060] Another example is shown in FIG. 16, where a robot arm 200 moves a
scan head 202 over multiple markers, for example on a patient's body. The
scanner head 202 may be directed by a physician to the markers, and then
instructed to apply a treatment. The robot arm may remember the position,
for example using kinematic information, and after the physician has
placed the scanner head at each treatment location, return automatically
to each of the locations so that multiple treatments may be applied to
the each location. Alternatively, the robot may remember a location, for
example via kinematics, and count the number of applications applied by a
physician. As still another alternative, the scanner head may include
optical recognition hardware, and may automatically find a marker and
apply a treatment.

[0061] The various parameters of the Energy Flux equation can be
programmed into the therapy controller. The apparatus may have some
parameter data programmed in fixed memory and not adjustable by the user.
Some elements may include maximum and minimum settings of the transducer
to prevent the apparatus from being operated in an unsafe manner.

[0062] A user can provide variables into the system to help the system
determine the proper EF to be used during a procedure. For example if the
user wishes to increase cooperative heating between scan lines, the scan
lines (nl) may be set to a higher value. Alternatively the velocity may
be reduced to promote larger halo fields, or the velocity may be
increased to decrease halo fields as might be required for regions of
adipose tissue which have smaller margins.

[0063] A stencil or template 24 can be used to assist a physician in
planning the treatment (FIG. 9). The template 24 has a series of
apertures 26 in the form of "crosshairs" which can be used to guide the
ultrasound transducer during the treatment procedure. The template 24
desirably is created so the apertures match the foot print of the
transducer to be used (or therapy device depending on the ultrasound
system selected). The template may be used across the skin prior to the
creation of contour lines or prior even to the evaluation of the adipose
tissue in the target region. Desirably a physician will mark the contour
lines and crosshair marks after making the determination of suitable
adipose tissue depth in the patients target treatment region.

[0064] The stencil 24 can be laid across the patient (FIG. 10) and then
the crosshairs drawn in using a medical marker. The combination of
crosshairs and contour lines shown in FIG. 1 combine to provide visual
markers for the safe placement of a HIFU transducer in an ordered fashion
(using the guide marks) within a known depth of adipose tissue (using the
contour lines). Once the two markings are on the patient, the physician
need only line up the ultrasound treatment device with the crosshairs and
contour lines (FIG. 2) to produce a mosaic of treatment sites 2 (FIG.
11).

[0065] The volume of tissue to be treated can be done using techniques
already adopted by physicians in the ordinary practice of procedures like
UAL. The physician can use a manual pinch test, calipers or diagnostic
ultrasound to determine the depth of the fat tissue to be treated and
draw circles around the region to be treated, similar to relief lines on
a topographical map. The individual marks from the stencil may be made
before the volume is determined, or after. The contour lines representing
varying levels of tissue volume, and therapy head land marks overlap to
provide the user with a defined safe area to treat, as well as a guide
for treatment using the ultrasound therapy head.

[0066] Proper utilization of the methods described herein can reduce the
volume of a region of adipose tissue. Histology slides of tissue using
the methods described herein are shown in FIGS. 12 and 13. These
histology pictures show both the skin line 12 and skin layer 14 are
undamaged. There is also shown a region of adipose tissue 16 having a
relatively safe depth for this type of treatment. The treatment zone is
found between the markers Z1 and Z2. Normal adipocytes (fat cells) 18 and
normal collagen fibrils 20 are shown between the skin layer 14 and the
treatment zone Z1. Within the treatment lines Z1, Z2 are shown two
regions of heavy collagen population and nearly complete lack of
adipocyte structures. The lesion field 22 shows both the collapse and
destruction of adipose tissue and the denaturing of collagen fibrils
which contract the tissue volume as the destroyed tissue mass is
gradually removed from the body (through the body's natural wound healing
response). The reduction of adipose tissue volume in this manner provides
a similar long term result to liposuction. Since the tissue loss is
gradual, there is no sudden looseness of the skin layer, nor skin
deformation observed immediately after a patient undergoes a treatment
using the methods described herein.

[0067] Review of the material disclosed herein will provide one skilled in
the art with numerous alternative methods of accomplishing the desired
objectives described, as well as methods not specifically mentioned
herein. The description provided should be taken as illustrative and
non-limiting, thus the present embodiments as well as alternative
embodiments and equivalents are intended to be captured by the
accompanying claims.